CN114553279A - Reconfigurable intelligent surface arbitrary beam forming method - Google Patents

Reconfigurable intelligent surface arbitrary beam forming method Download PDF

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CN114553279A
CN114553279A CN202210104264.6A CN202210104264A CN114553279A CN 114553279 A CN114553279 A CN 114553279A CN 202210104264 A CN202210104264 A CN 202210104264A CN 114553279 A CN114553279 A CN 114553279A
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intelligent surface
reflection coefficient
reconfigurable
reconfigurable intelligent
dimension
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党建
李业伟
张在琛
吴亮
朱秉诚
汪磊
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Southeast University
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0617—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal for beam forming
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/04013—Intelligent reflective surfaces
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

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  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
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Abstract

The invention discloses a reconfigurable intelligent surface arbitrary beam forming method, which is a flexible beam forming method capable of generating arbitrary beam quantity, beam space direction, beam cross section shape and beam internal power distribution aiming at the diversity requirement of reconfigurable surface auxiliary mobile communication. Compared with the existing beam forming method, the method disclosed by the invention has the advantage of obviously better beam forming effect.

Description

Reconfigurable intelligent surface arbitrary beam forming method
Technical Field
The invention belongs to the technical field of wireless communication, and particularly relates to a reconfigurable intelligent surface arbitrary beam forming method.
Background
With the rapid increase in the demand of wireless communication applications, the mobile communication spectrum is continuously expanding to high frequencies. While the bandwidth is increased, the high-frequency electromagnetic wave also has the problem of serious path loss, and coverage holes and blind areas are easy to form. In recent years, with the development of artificial electromagnetic materials, new technologies represented by Reconfigurable Intelligent Surface (RIS) are introduced into wireless communication. The RIS can change the transmission behavior of electromagnetic waves macroscopically by cooperatively configuring the reflection coefficients of a large number of micro reflection units, and realize various beam forming effects such as beam focusing, splitting and scattering, so that the coverage problem of high-frequency electromagnetic waves is hopefully solved to a certain extent.
The existing RIS beamforming mainly focuses on indexes such as a receiving signal-to-noise ratio of a specific user, and does not focus on the design of a beam shape in a physical space. However, in mobile communication, since the location information of the user is difficult to obtain accurately and is in a moving state, the beamforming method using the signal-to-noise ratio as an index has strong sensitivity to location error and movement, and the link robustness is poor. In some scenarios, the base station needs to transmit a wider beam for information broadcasting. The above scenarios show that it is necessary to design an arbitrary beamforming method for RIS, so that the shape, width, angle, and power of the beam can be arbitrarily adjusted to meet the requirements of various scenarios in mobile communications, and the design needs to have low complexity for fast switching of the beam. At present, only a beam forming method designed by using a frequency domain sampling method is reported in documents, but the method can achieve a certain forming effect only under special conditions of enough units, uniform beam power distribution and the like, and actual requirements are difficult to meet.
Disclosure of Invention
The purpose of the invention is as follows: aiming at the RIS beam forming requirements and requirements mentioned in the background technology and the defects of the existing method, the invention provides a reconfigurable intelligent surface arbitrary beam forming method, which has low realization complexity under the condition that parameters such as beam shape, width, power and the like can be adjusted arbitrarily, thereby providing a beam forming technical route for the practical deployment and application of RIS in mobile communication.
The technical scheme is as follows: in order to achieve the purpose, the invention adopts the technical scheme that:
a reconfigurable intelligent surface arbitrary beam forming method comprises the following steps:
step 1, configuring a reconfigurable intelligent surface to be N1×N2Two-dimensional rectangular planes of individual cells, spaced at d meters, placed at far field locations of a base station, record the azimuth (i.e., horizontal angle) phi of incident beams from the base station to the reconfigurable intelligent surfaceinAnd a pitch angle
Figure BDA0003493339750000011
Step 2, setting an ideal three-dimensional reflection beam pattern according to application requirements, wherein the ideal three-dimensional reflection beam pattern comprises the number of beams, the direction of each beam, the cross section shape of each beam and the power ratio of different areas of the cross section, and mapping the parameters to a two-dimensional angle domain function
Figure BDA0003493339750000021
One of the dimensions is the azimuth angle phioutThe other dimension being pitch angle
Figure BDA0003493339750000022
Function value
Figure BDA0003493339750000023
Is shown at an azimuth angle phioutAnd a pitch angle
Figure BDA0003493339750000024
Normalized amplitude value of direction-allocated beam response, its square
Figure BDA0003493339750000025
Is shown at an azimuth angle phioutAnd a pitch angle
Figure BDA0003493339750000026
Normalized power values of the direction allocated beam responses.
Step 3, function
Figure BDA0003493339750000027
Mapping to another two-dimensional angular domain function H using the following rule1(ω1,ω2)：
Figure BDA0003493339750000028
Figure BDA0003493339750000029
Figure BDA00034933397500000210
Wherein λ is the carrier wavelength of the system operating frequency band.
Step 4, for function H1(ω1,ω2) Performing uniform sampling, wherein in the dimension omega1The number of upsampled points is recorded as M1In the dimension ω2The number of upsampled points is recorded as M2，M1，M2Respectively satisfy M1≥N1，M2≥N2And should be as large as possible, and finally the sampled function value is recorded as H1(ω1,k,ω2,l) Where k and l each represent the dimension ω1And dimension ω2The sample number of (c).
Step 5, configuring the n-th reconfigurable surface1Line, n-th2The reflection coefficient of each column of reflection units is
Figure BDA00034933397500000211
Wherein
Figure BDA00034933397500000212
0≤n2≤N2-1. The reflection coefficient of the other half cell is given by the following equation:
v(n1,n2)＝v*(N1-1-n1,N2-1-n2)，
Figure BDA00034933397500000213
0≤n2≤N2-1.
and configuring the reflection coefficient of the reconfigurable intelligent surface according to the formula to finish any beam forming.
In practice, due to reasons such as manufacturing processes, the unit reflection coefficient of the reconfigurable intelligent surface can only take a limited number of values, and the common conditions and the coefficient setting method thereof are summarized as follows:
case 1: the reflection coefficient amplitude value needs to be less than or equal to 1, and both the amplitude and the phase are continuously taken.
Reflection coefficient setting method of case 1: setting the reflection coefficient to
Figure BDA00034933397500000214
Case 2: the reflection coefficient amplitude value needs to be less than or equal to 1, and both the amplitude and the phase can only take a plurality of discrete values.
Reflection coefficient setting method of case 2: setting the reflection coefficient to v(2)(n1,n2)，v(2)(n1,n2) Of a limited number of possible values of all reflection coefficients, the distance v(1)(n1,n2) More recently.
Case 3: the reflection coefficient amplitude value is equal to 1 and the phase takes a finite number of discrete values.
Reflection coefficient setting method of case 3: setting the reflection coefficient to v(3)(n1,n2)＝exp(j∠v(n1,n2) Is less than v (n)1,n2) Denotes a value of v (n)1,n2) Phase.
Compared with the prior art, the invention has the following beneficial effects:
the invention can shape the reflection wave beam of the reconfigurable intelligent surface at will, has higher application flexibility, and simultaneously has extremely low calculation complexity, thereby being beneficial to the quick switching and establishment of the reflection state of the reconfigurable intelligent surface.
Drawings
FIG. 1 illustrates the azimuth and elevation coverage of a beam in example one;
FIG. 2 illustrates coverage of a beam after azimuth and elevation angles are mapped to a two-dimensional angular domain in example one;
FIG. 3 is a diagram illustrating a beam pattern designed using the method of the present invention;
FIG. 4 is a graph showing the effect of beam comparison between the method of the present invention and frequency sampling;
FIG. 5 illustrates the azimuth and elevation coverage of a beam in example two;
FIG. 6 is a beam pattern designed from the reflection coefficients quantized by the method of the present invention in example two;
FIG. 7 is a graph comparing the effect of the method of the present invention on the desired amplitude for a given azimuth angle in example two;
fig. 8 is a graph comparing the effect of the method of the present invention on the ideal amplitude for a given pitch angle in example two.
Detailed Description
The present invention is further illustrated by the following description in conjunction with the accompanying drawings and the specific embodiments, it is to be understood that these examples are given solely for the purpose of illustration and are not intended as a definition of the limits of the invention, since various equivalent modifications will occur to those skilled in the art upon reading the present invention and fall within the limits of the appended claims.
The first embodiment is as follows:
a reconfigurable intelligent surface arbitrary beam forming method comprises the following steps:
step 1, configuring a reconfigurable intelligent surface to be N1×N2A two-dimensional rectangular plane of 32 × 32 cells with cell spacing
Figure BDA0003493339750000031
Meter, where λ is the carrier wavelength, placing the reconfigurable intelligent surface in the far field location of the base station, the azimuth (i.e., horizontal) angle φ of the incident beam from the base station to the reconfigurable intelligent surfacein60 ° and pitch angle
Figure BDA0003493339750000032
Step 2, it is assumed that there are two users whose positioning information is not accurate enough, and therefore, two relatively wide beams need to be generated to point to the two users respectively. Where the azimuth range of the beam of user 1 is 0.4 pi, 0.8 pi, the pitch range is 0.1 pi, 0.4 pi, the azimuth range of the beam of user 2 is 1.4 pi, 1.65 pi, the pitch range is 0.2 pi, 0.45 pi, and their amplitude values are set to 1, as shown in fig. 1.
Step 3, function
Figure BDA0003493339750000033
Mapping to another two-dimensional angular domain function H using the following rule1(ω1,ω2)：
Figure BDA0003493339750000041
Figure BDA0003493339750000042
Figure BDA0003493339750000043
Wherein, by substituting the above values, ω corresponding to the beam 1 and the beam 2 can be obtained1And omega2In the above range, H1(ω1,ω2) The value is 1 as shown in fig. 2.
Step 4, for function H1(ω1,ω2) Performing uniform sampling, wherein in the dimension omega1The number of upsampled points is recorded as M1100 in the dimension ω2The number of upsampled points is recorded as M2The value of the function after sampling is recorded as H (100)1(ω1,k,ω2,l) Where k and l each represent the dimension ω1And dimension ω2The sample number of (c).
Step 5, configuring the n-th reconfigurable surface1Line, n-th2The reflection coefficient of each column of reflection units is
Figure BDA0003493339750000044
Wherein
Figure BDA0003493339750000045
The reflection coefficient of the other half cell is given by the following equation:
v(n1,n2)＝v*(N1-1-n1,N2-1-n2)，
Figure BDA0003493339750000046
in this embodiment, the unit reflection coefficient amplitude value of the reconfigurable intelligent surface needs to be less than or equal to 1, the amplitude and the phase can be continuously valued, and at this time, the reflection coefficient is set to be
Figure BDA0003493339750000047
The pattern of the reconfigurable smart surface reflected beam is examined using the reflection coefficients described above, as shown in fig. 3, in close proximity to the desired shape of fig. 1. Fig. 4 shows a comparison effect diagram of beams obtained by the method of the present invention and a frequency sampling method under the condition that the given pitch angle is 0.25 pi, and it can be seen that the beam forming effect of the method of the present invention is better.
Example two:
a reconfigurable intelligent surface arbitrary beam forming method comprises the following steps:
step 1, configuring a reconfigurable intelligent surface to be N1×N2A two-dimensional rectangular plane of 32 × 32 cells with cell spacing of
Figure BDA0003493339750000048
M, where λ is the carrier wavelength, placing the reconfigurable smart surface at the far field location of the base station, the azimuth (i.e., horizontal) angle phi of the incident beam from the base station to the reconfigurable smart surfacein60 ° and pitch angle
Figure BDA0003493339750000049
Step 2, assuming that there is a single user, the user is in a constant-speed moving state, and in order to ensure stable communication, a rectangular reflected beam with uniform power needs to be allocated to the user, assuming that the azimuth angle range of the beam is [0.3 pi, 0.7 pi ], the pitch angle range is [0.1 pi, 0.2 pi ], and the amplitude value is set to 1, as shown in fig. 5.
Step 3, function
Figure BDA0003493339750000051
Mapping to another two-dimensional angular domain function H using the following rule1(ω1,ω2)：
Figure BDA0003493339750000052
Figure BDA0003493339750000053
Figure BDA0003493339750000054
Wherein, substituting the above value, the corresponding omega of the beam1And ω2In the range of H1(ω11,ω2) The value is 1.
Step 4, for function H1(ω11,ω2) Performing uniform sampling, wherein in the dimension omega1The number of upsampled points is recorded as M1100 in the dimension ω2The number of upsampling points is recorded as M2The value of the function after sampling is recorded as H (100)1(ω11,k,ω2,l) Where k and l each represent the dimension ω1And dimension ω2The sample number of (c).
Step 5, configuring the n-th reconfigurable surface1Line, n-th2The reflection coefficient of each column of reflection units is
Figure BDA0003493339750000055
Wherein
Figure BDA0003493339750000056
The reflection coefficient of the other half cell is given by the following equation:
v(n1,n2)＝v*(N1-1-n1,N2-1-n2)，
Figure BDA0003493339750000057
in this embodiment, the unit reflection coefficient amplitude value of the reconfigurable intelligent surface needs to be less than or equal to 1, and the amplitude and the phase are respectively represented by 3 bits in a quantization manner, that is, the amplitude and the phase can only respectively take 8 discrete values, and at this time, the reflection coefficient is set as v(2)(n1,n2)，v(2)(n1,n2) Is the distance of the finite number of possible values of all reflection coefficients
Figure BDA0003493339750000058
More recently. The pattern of the reconfigurable smart surface reflected beam is examined using the reflection coefficients described above, as shown in fig. 6. Fig. 7 shows a graph of the effect of the amplitude correspondence in this example on the ideal amplitude correspondence for an azimuth angle of 0.5 pi. Fig. 8 shows a comparison effect graph of the amplitude correspondence in the present embodiment with the ideal amplitude correspondence for a pitch angle of 0.15 pi. It can be observed from the figure that the method of the present invention can still obtain a good beamforming effect after the amplitude and the phase of the reflection coefficient are dispersed, and therefore, the method is an advantageous candidate method for arbitrary beamforming.
The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.

Claims (5)

1. A reconfigurable intelligent surface arbitrary beam forming method is characterized by comprising the following steps:
step 1, configuring a reconfigurable intelligent surface to be N1×N2Two-dimensional rectangular plane of each unit, the unit interval is d meters, the two-dimensional rectangular plane is placed at the far field position of the base station, and the azimuth angle and the pitch angle of an incident beam from the base station to the reconfigurable intelligent surface are recorded
Figure FDA0003493339740000011
Step 2, setting an expected three-dimensional reflection beam pattern according to application requirements, and mapping beam information to a two-dimensional angle domain function
Figure FDA0003493339740000012
One of the dimensions is the azimuth angle phioutThe other dimension being pitch angle
Figure FDA0003493339740000013
Function value
Figure FDA0003493339740000014
Is shown at an azimuth angle phioutAnd a pitch angle
Figure FDA0003493339740000015
Normalized amplitude values of the directionally assigned beam responses;
step 3, function
Figure FDA0003493339740000016
Mapping to another two-dimensional angular domain function H using the following rule1(ω1,ω2)：
Figure FDA0003493339740000017
Figure FDA0003493339740000018
Figure FDA0003493339740000019
Wherein, λ is the carrier wavelength of the system working frequency band;
step 4, for function H1(ω1,ω2) Performing uniform sampling, wherein in the dimension omega1The number of upsampled points is recorded as M1In the dimension ω2The number of upsampled points is recorded as M2，M1、M2Respectively satisfy M1≥N1、M2≥N2Finally, the function value after sampling is recorded as H1(ω1,k,ω2,l) Where k and l each represent the dimension ω1And dimension ω2The sampling sequence number of the upper;
step 5, configuring the n-th reconfigurable surface1Line, n-th2The reflection coefficient of each column of reflection units is
Figure FDA00034933397400000110
Wherein
Figure FDA00034933397400000111
The reflection coefficient of the other half cell is given by the following equation:
v(n1,n2)=v*(N1-1-n1,N2-1-n2)，
Figure FDA00034933397400000112
0≤n2≤N2-1。
2. according to claim 1The reconfigurable intelligent surface arbitrary beam forming method is characterized by comprising the following steps: dimension ω in step 41And ω2The sampling point selection modes are respectively as follows:
Figure FDA00034933397400000113
Figure FDA00034933397400000114
3. the reconfigurable intelligent surface arbitrary beamforming method of claim 1, wherein: when the unit reflection coefficient amplitude value of the reconfigurable intelligent surface needs to be less than or equal to 1, and the amplitude and the phase are continuously valued, setting the reflection coefficient as
Figure FDA0003493339740000021
4. The reconfigurable intelligent surface arbitrary beamforming method of claim 1, wherein: when the unit reflection coefficient amplitude value of the reconfigurable intelligent surface needs to be less than or equal to 1, and the amplitude and the phase can only take a plurality of discrete values, setting the reflection coefficient as v(2)(n1,n2) Wherein v is(2)(n1,n2) Is the distance of the finite number of possible values of all reflection coefficients
Figure FDA0003493339740000022
More recently.
5. The reconfigurable intelligent surface arbitrary beamforming method of claim 1, wherein: when the unit reflection coefficient amplitude value of the reconfigurable intelligent surface needs to be equal to 1, and the phase takes a finite number of discrete values, setting the reflection coefficient as v(3)(n1,n2)＝exp(j∠v(n1,n2) Is less than v (n)1,n2) Denotes a value of v (n)1,n2) Phase.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024103331A1 (en) * 2022-11-17 2024-05-23 Qualcomm Incorporated Report of minimum reflection beam amount in a reconfigurable intelligent surface (ris) -based sensing system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024103331A1 (en) * 2022-11-17 2024-05-23 Qualcomm Incorporated Report of minimum reflection beam amount in a reconfigurable intelligent surface (ris) -based sensing system

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